You guys are all so far off I am wondering if I should bother posting...
The OP wants a loss of Oil pressure procedure...and no one has stated an aircraft that doesn't have one..
As far as losing oil pressure, that's not a direct indication of oil quantity...could be a bad sensor, or indicator, ect...but as a general rule you don't put an indicator on a plane without telling the pilot what it means..or providing a solution if that indicator gets into the red, ect.
Which means the OP is putting all you guys on...you fell for it, and jumped into a furball, jumping back and forth pushing the thread into areas that had just about nothing to do with the original question. Classic Troll bait, with the resident experts showing just how little they know on the subject at hand. Classic.
If you disagree, send me a normal plane that doesn't not have any reference to the oil pressure indicator in the manual or checklist.